Moved a lot of things to have explicit alloc arguments

Changed Table to be stateless

build.zig

@@ -58,6 +58,7 @@ pub fn build(b: *std.Build) !void {
 
     b.installArtifact(lib);
     b.installArtifact(exe);
+
     const run_step = b.step("run", "Run the app");
     const run_cmd = b.addRunArtifact(exe);
     run_step.dependOn(&run_cmd.step);
@@ -76,4 +77,12 @@ pub fn build(b: *std.Build) !void {
     const test_step = b.step("test", "Run tests");
     test_step.dependOn(&run_mod_tests.step);
     test_step.dependOn(&run_exe_tests.step);
+
+    // Wanted by ZLS for better detection.
+    const exe_check = b.addExecutable(.{
+        .name = "unsquashfs",
+        .root_module = mod,
+    });
+    const check = b.step("check", "Check if unsquashfs compiles");
+    check.dependOn(&exe_check.step);
 }

src/archive.zig

@@ -31,121 +31,66 @@ pub const FragEntry = packed struct {
 
 const Archive = @This();
 
-// 4 Gigs
-const DEFAULT_MEM_SIZE = 4 * 1024 * 1024 * 1024;
-
-parent_alloc: std.mem.Allocator,
-alloc: std.heap.ThreadSafeAllocator,
-// alloc: std.heap.FixedBufferAllocator,
-// fixed_buf: []u8,
-thread_count: usize,
-
 fil: OffsetFile,
 
 super: Superblock,
 
-setup: bool = false,
-
 decomp: Decomp.DecompFn,
 
-frag_table: Table(FragEntry) = undefined,
+frag_table: Table(FragEntry),
-id_table: Table(u16) = undefined,
+id_table: Table(u16),
-export_table: Table(InodeRef) = undefined,
+export_table: Table(InodeRef),
 
-/// Default settings using std.Thread.getCpuCount() threads and the minimum of 4gb or half of system memory for memory usage.
+/// Begin reading a squashfs archive from the given File at the given offset.
-pub fn init(alloc: std.mem.Allocator, fil: File) !Archive {
+pub fn init(fil: File, offset: u64) !Archive {
-    return initAdvanced(
-        alloc,
-        fil,
-        0,
-        try std.Thread.getCpuCount(),
-    );
-}
-/// Create the Archive dictating the amount of threads used for extraction.
-/// If you're planning on only interacting with a small number of files, it should be fine to use few (or one) threads.
-pub fn initAdvanced(alloc: std.mem.Allocator, fil: File, offset: u64, threads: usize) !Archive {
     var super: Superblock = undefined;
-    const red = try fil.pread(@ptrCast(&super), offset);
+    _ = try fil.pread(@ptrCast(&super), offset);
-    std.debug.assert(red == @sizeOf(Superblock));
     try super.validate();
-    // const fixed_buf = try alloc.alloc(u8, mem);
+    const decomp: Decomp.DecompFn = switch (super.compression) {
-    return .{
-        .parent_alloc = alloc,
-        .alloc = .{ .child_allocator = alloc },
-        // .fixed_buf = fixed_buf,
-        .thread_count = if (threads > 0) threads else try std.Thread.getCpuCount(),
-        .fil = .init(fil, offset),
-        .decomp = switch (super.compression) {
         .gzip => Decomp.gzipDecompress,
         .lzma => Decomp.lzmaDecompress,
         .xz => Decomp.xzDecompress,
         .zstd => Decomp.zstdDecompress,
         .lz4 => if (config.use_c_libs) Decomp.cLz4 else return error.Lz4Unsupported,
         .lzo => if (config.use_c_libs and config.allow_lzo) Decomp.lzoDecompress else return error.LzoUnsupported,
-        },
+    };
-
+    const offset_fil: OffsetFile = .init(fil, offset);
+    return .{
+        .fil = offset_fil,
         .super = super,
+
+        .decomp = decomp,
+
+        .frag_table = .init(offset_fil, decomp, super.frag_start, super.frag_count),
+        .id_table = .init(offset_fil, decomp, super.id_start, super.id_count),
+        .export_table = .init(offset_fil, decomp, super.export_start, super.inode_count),
     };
 }
-pub fn deinit(self: *Archive) void {
-    // self.parent_alloc.free(self.fixed_buf);
-    if (self.setup) {
-        self.frag_table.deinit();
-        self.export_table.deinit();
-        self.id_table.deinit();
-    }
-}
 
-pub fn allocator(self: *Archive) std.mem.Allocator {
+pub fn inode(self: Archive, num: u32) !Inode {
-    return self.alloc.allocator();
-}
-
-fn setupValues(self: *Archive) !void {
-    const alloc = self.allocator();
-    self.frag_table = try .init(alloc, self.fil, self.decomp, self.super.frag_start, self.super.frag_count);
-    self.id_table = try .init(alloc, self.fil, self.decomp, self.super.id_start, self.super.id_count);
-    self.export_table = try .init(alloc, self.fil, self.decomp, self.super.export_start, self.super.inode_count);
-    self.setup = true;
-}
-
-pub fn id(self: *Archive, idx: u32) !u16 {
-    if (!self.setup) try self.setupValues();
-    return self.id_table.get(idx);
-}
-
-pub fn frag(self: *Archive, idx: u32) !FragEntry {
-    if (!self.setup) try self.setupValues();
-    return self.frag_table.get(idx);
-}
-
-pub fn inode(self: *Archive, num: u32) !Inode {
     if (!self.setup) try self.setupValues();
     const ref = try self.export_table.get(num - 1);
     var rdr = try self.fil.readerAt(ref.block_start + self.super.inode_start, &[0]u8{});
-    var meta: MetadataReader = .init(self.allocator(), &rdr.interface, &self.decomp);
+    var meta: MetadataReader = .init(self.alloc, &rdr.interface, &self.decomp);
     try meta.interface.discardAll(ref.block_offset);
-    return try .read(self.allocator(), &meta.interface, self.super.block_size);
+    return try .read(self.alloc, &meta.interface, self.super.block_size);
 }
 
-pub fn root(self: *Archive) !SfsFile {
+pub fn root(self: Archive, alloc: std.mem.Allocator) !SfsFile {
-    if (!self.setup) try self.setupValues();
     var rdr = try self.fil.readerAt(self.super.root_ref.block_start + self.super.inode_start, &[0]u8{});
-    var meta: MetadataReader = .init(self.allocator(), &rdr.interface, self.decomp);
+    var meta: MetadataReader = .init(alloc, &rdr.interface, self.decomp);
     try meta.interface.discardAll(self.super.root_ref.block_offset);
-    const in: Inode = try .read(self.allocator(), &meta.interface, self.super.block_size);
+    const in: Inode = try .read(alloc, &meta.interface, self.super.block_size);
-    return .init(self, in, "");
+    return .init(alloc, self, in, "");
 }
 
-pub fn open(self: *Archive, path: []const u8) !SfsFile {
+pub fn open(self: Archive, alloc: std.mem.Allocator, path: []const u8) !SfsFile {
-    if (!self.setup) try self.setupValues();
+    var root_fil = try self.root(alloc);
-    var root_fil = try self.root();
     defer if (!SfsFile.pathIsSelf(path)) root_fil.deinit();
-    return root_fil.open(path);
+    return root_fil.open(alloc, path);
 }
 
-pub fn extract(self: *Archive, path: []const u8, options: ExtractionOptions) !void {
+pub fn extract(self: Archive, alloc: std.mem.Allocator, path: []const u8, options: ExtractionOptions) !void {
-    if (!self.setup) try self.setupValues();
-    var alloc = self.allocator();
     var ext_path: []u8 = undefined;
     if (std.fs.cwd().statFile(path)) |stat| {
         if (stat.kind == .directory) {
@@ -161,8 +106,8 @@ pub fn extract(self: *Archive, path: []const u8, options: ExtractionOptions) !vo
     }
     defer if (ext_path.len > path.len) alloc.free(ext_path);
     var rdr = try self.fil.readerAt(self.super.root_ref.block_start + self.super.inode_start, &[0]u8{});
-    var meta: MetadataReader = .init(self.allocator(), &rdr.interface, self.decomp);
+    var meta: MetadataReader = .init(alloc, &rdr.interface, self.decomp);
     try meta.interface.discardAll(self.super.root_ref.block_offset);
-    const in: Inode = try .read(self.allocator(), &meta.interface, self.super.block_size);
+    const in: Inode = try .read(alloc, &meta.interface, self.super.block_size);
-    try in.extractToThreaded(self, ext_path, options, self.thread_count);
+    try in.extractTo(alloc, self, ext_path, options);
 }

src/bin/unsquashfs.zig

@@ -44,9 +44,8 @@ pub fn main() !void {
     }
     var fil: std.fs.File = try std.fs.cwd().openFile(archive, .{}); //TODO: Handle error gracefully.
     defer fil.close();
-    var arc: squashfs.Archive = try .initAdvanced(alloc, fil, offset, threads); //TODO: Update when memory size matters. //TODO: Handle error gracefully.
+    var arc: squashfs.Archive = try .init(fil, offset); //TODO: Update when memory size matters. //TODO: Handle error gracefully.
-    defer arc.deinit();
+    try arc.extract(alloc, extLoc, if (verbose) try .VerboseDefault(&out.interface) else try .Default()); //TODO: Handle error gracefully.
-    try arc.extract(extLoc, if (verbose) .VerboseDefault(&out.interface) else .Default); //TODO: Handle error gracefully.
 }
 
 fn handleArgs(alloc: std.mem.Allocator, out: *Writer) !void {

src/decomp.zig

@@ -29,6 +29,7 @@ pub const CompressionType = enum(u16) {
     zstd,
 };
 
+/// A generic decompression function. alloc is only used for internal use and any allocations made will be freed.
 pub const DecompFn = *const fn (alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize; // TODO: replace anyerror to definitive error types.
 
 pub const gzipDecompress = if (config.use_c_libs) cGzip else zigGzip;

src/file.zig

@@ -24,39 +24,40 @@ const FileError = error{
 
 const SfsFile = @This();
 
-archive: *Archive,
+alloc: std.mem.Allocator,
+archive: Archive,
 
 inode: Inode,
 name: []const u8,
 
 /// Initialize a new File.
 /// name is copied to the File so can be safely freed afterwards.
-pub fn init(archive: *Archive, inode: Inode, name: []const u8) !SfsFile {
+pub fn init(alloc: std.mem.Allocator, archive: Archive, inode: Inode, name: []const u8) !SfsFile {
-    const new_name = try archive.allocator().alloc(u8, name.len);
+    const new_name = try alloc.alloc(u8, name.len);
     @memcpy(new_name, name);
     return .{
+        .alloc = alloc,
         .archive = archive,
         .inode = inode,
         .name = new_name,
     };
 }
-pub fn fromEntry(archive: *Archive, entry: DirEntry) !SfsFile {
+pub fn fromEntry(alloc: std.mem.Allocator, archive: Archive, entry: DirEntry) !SfsFile {
     var rdr = try archive.fil.readerAt(entry.block_start + archive.super.inode_start, &[0]u8{});
-    var meta: MetadataReader = .init(archive.allocator(), &rdr.interface, archive.decomp);
+    var meta: MetadataReader = .init(alloc, &rdr.interface, archive.decomp);
     try meta.interface.discardAll(entry.block_offset);
-    const inode: Inode = try .read(archive.allocator(), &meta.interface, archive.super.block_size);
+    const inode: Inode = try .read(alloc, &meta.interface, archive.super.block_size);
-    errdefer inode.deinit(archive.allocator());
+    errdefer inode.deinit(alloc);
-    return .init(archive, inode, entry.name);
+    return .init(alloc, archive, inode, entry.name);
 }
 
 pub fn deinit(self: SfsFile) void {
-    var alloc = self.archive.allocator();
+    self.alloc.free(self.name);
-    alloc.free(self.name);
+    self.inode.deinit(self.alloc);
-    self.inode.deinit(alloc);
 }
 
-fn getEntries(self: SfsFile) ![]DirEntry {
+fn getEntries(self: SfsFile, alloc: std.mem.Allocator) ![]DirEntry {
-    return self.inode.dirEntries(self.archive.allocator(), self.archive.*);
+    return self.inode.dirEntries(alloc, self.archive);
 }
 
 pub fn ownerUid(self: SfsFile) !u16 {
@@ -96,20 +97,19 @@ pub fn iterate(self: SfsFile) !Iterator {
 }
 /// Open a sub-file/folder within a directory at the given path.
 /// If path is "", ".", "/", or "./", this File is returned.
-pub fn open(self: SfsFile, path: []const u8) !SfsFile {
+pub fn open(self: SfsFile, alloc: std.mem.Allocator, path: []const u8) !SfsFile {
     if (!self.isDir()) return FileError.NotDirectory;
     if (pathIsSelf(path)) return self;
 
     // Recursively stip ending & leading path separators.
-    if (path[0] == '/') return self.open(path[1..]);
+    if (path[0] == '/') return self.open(alloc, path[1..]);
-    if (path[path.len - 1] == '/') return self.open(path[0 .. path.len - 1]);
+    if (path[path.len - 1] == '/') return self.open(alloc, path[0 .. path.len - 1]);
 
     const idx = std.mem.indexOf(u8, path, "/") orelse path.len;
     const first_element = path[0..idx];
-    if (std.mem.eql(u8, first_element, ".")) return self.open(path[idx + 1 ..]);
+    if (std.mem.eql(u8, first_element, ".")) return self.open(alloc, path[idx + 1 ..]);
-    const entries = try self.getEntries();
+    const entries = try self.getEntries(alloc);
     defer {
-        var alloc = self.archive.allocator();
         for (entries) |e| {
             e.deinit(alloc);
         }
@@ -122,12 +122,12 @@ pub fn open(self: SfsFile, path: []const u8) !SfsFile {
         const comp = std.mem.order(u8, first_element, cur_slice[split].name);
         switch (comp) {
             .eq => {
-                var fil: SfsFile = try .fromEntry(self.archive, cur_slice[split]);
+                var fil: SfsFile = try .fromEntry(alloc, self.archive, cur_slice[split]);
                 if (idx == path.len) {
                     return fil;
                 }
                 defer fil.deinit();
-                return fil.open(path[idx + 1 ..]);
+                return fil.open(alloc, path[idx + 1 ..]);
             },
             .lt => cur_slice = cur_slice[0..split],
             .gt => cur_slice = cur_slice[split + 1 ..],
@@ -170,35 +170,8 @@ pub fn devNum(self: SfsFile) !u32 {
 
 /// Extract the given File to the path. If File is a regular file, the path must be a directory or not exist.
 /// If the gievn path is a folder, the File's contents will be extracted within.
-pub fn extract(self: *SfsFile, path: []const u8, options: ExtractionOptions) !void {
+pub fn extract(self: SfsFile, alloc: std.mem.Allocator, path: []const u8, options: ExtractionOptions) !void {
-    var alloc = self.archive.allocator();
+    return self.inode.extractTo(alloc, self.archive, path, options);
-    var ext_path: []u8 = undefined;
-    if (std.fs.cwd().statFile(path)) |stat| {
-        if (stat.kind == .directory) {
-            if (!self.isDir()) {
-                const has_end_sep = path[path.len - 1] == '/';
-                const alloc_size = if (has_end_sep)
-                    path.len + self.name.len
-                else
-                    path.len + self.name.len + 1;
-                ext_path = try alloc.alloc(u8, alloc_size);
-                @memcpy(ext_path[0..path.len], path);
-                @memcpy(ext_path[ext_path.len - self.name.len ..], self.name);
-                if (!has_end_sep) ext_path[path.len] = '/';
-            } else {
-                ext_path = @constCast(path);
-            }
-        } else return FileError.ExtractionPathExists;
-    } else |err| {
-        if (err == error.FileNotFound) {
-            ext_path = @constCast(path);
-        } else {
-            std.log.err("Error stat-ing extraction path {s}: {}\n", .{ path, err });
-            return err;
-        }
-    }
-    defer if (ext_path.len > path.len) alloc.free(ext_path);
-    return self.inode.extractToThreaded(self.archive, path, options, self.archive.thread_count);
 }
 
 /// Utility function.
@@ -210,8 +183,10 @@ pub fn pathIsSelf(path: []const u8) bool {
 }
 
 pub const Iterator = struct {
+    alloc: std.mem.Allocator,
+
     entries: []DirEntry,
-    archive: *Archive,
+    archive: Archive,
 
     idx: u32 = 0,
 
@@ -221,10 +196,9 @@ pub const Iterator = struct {
         return try SfsFile.fromEntry(self.archive, self.entries[self.idx]);
     }
     pub fn deinit(self: Iterator) void {
-        var alloc = self.archive.allocator();
         for (self.entries) |e| {
-            e.deinit(alloc);
+            e.deinit(self.alloc);
         }
-        alloc.free(self.entries);
+        self.alloc.free(self.entries);
     }
 };

src/inode.zig

@@ -93,7 +93,7 @@ pub fn read(alloc: std.mem.Allocator, rdr: *Reader, block_size: u32) !Inode {
         },
     };
 }
-pub fn readFromEntry(alloc: std.mem.Allocator, archive: *Archive, entry: DirEntry) !Inode {
+pub fn readFromEntry(alloc: std.mem.Allocator, archive: Archive, entry: DirEntry) !Inode {
     var rdr = try archive.fil.readerAt(archive.super.inode_start + entry.block_start, &[0]u8{});
     var meta: MetadataReader = .init(alloc, &rdr.interface, archive.decomp);
     try meta.interface.discardAll(entry.block_offset);
@@ -111,32 +111,42 @@ pub fn deinit(self: Inode, alloc: std.mem.Allocator) void {
 }
 
 /// Get the data reader for a file inode.
-pub fn dataReader(self: Inode, alloc: std.mem.Allocator, archive: *Archive) !DataReader {
+pub fn dataReader(self: Inode, alloc: std.mem.Allocator, archive: Archive) !DataReader {
     return switch (self.hdr.inode_type) {
         .file => readerFromData(alloc, archive, self.data.file),
         .ext_file => readerFromData(alloc, archive, self.data.ext_file),
         else => error.NotRegularFile,
     };
 }
-fn readerFromData(alloc: std.mem.Allocator, archive: *Archive, data: anytype) !DataReader {
+fn readerFromData(alloc: std.mem.Allocator, archive: Archive, data: anytype) !DataReader {
-    var out: DataReader = .init(alloc, archive.*, data.block_sizes, data.block_start, data.size);
+    return .init(
-    if (data.frag_idx != 0xFFFFFFFF)
+        alloc,
-        out.addFragment(try archive.frag(data.frag_idx), data.frag_block_offset);
+        archive,
-    return out;
+        data.block_sizes,
+        data.block_start,
+        data.size,
+        data.frag_block_offset,
+        if (data.frag_idx == 0xFFFFFFFF) null else try archive.frag_table.get(alloc, data.frag_idx),
+    );
 }
 /// Get a threaded data reader for a file inode.
-pub fn threadedDataReader(self: Inode, alloc: std.mem.Allocator, archive: *Archive) !ThreadedDataReader {
+pub fn threadedDataReader(self: Inode, alloc: std.mem.Allocator, archive: Archive) !ThreadedDataReader {
     return switch (self.hdr.inode_type) {
         .file => threadedReaderFromData(alloc, archive, self.data.file),
         .ext_file => threadedReaderFromData(alloc, archive, self.data.ext_file),
         else => error.NotRegularFile,
     };
 }
-fn threadedReaderFromData(alloc: std.mem.Allocator, archive: *Archive, data: anytype) !ThreadedDataReader {
+fn threadedReaderFromData(alloc: std.mem.Allocator, archive: Archive, data: anytype) !ThreadedDataReader {
-    var out: ThreadedDataReader = .init(alloc, archive.*, data.block_sizes, data.block_start, data.size);
+    return .init(
-    if (data.frag_idx != 0xFFFFFFFF)
+        alloc,
-        out.addFragment(try archive.frag(data.frag_idx), data.frag_block_offset);
+        archive,
-    return out;
+        data.block_sizes,
+        data.block_start,
+        data.size,
+        data.frag_block_offset,
+        if (data.frag_idx == 0xFFFFFFFF) null else try archive.frag_table.get(alloc, data.frag_idx),
+    );
 }
 
 /// Get the directory entries for a directory inode.
@@ -154,17 +164,17 @@ fn entriesFromData(alloc: std.mem.Allocator, archive: Archive, data: anytype) ![
     return DirEntry.readDir(alloc, &meta.interface, data.size);
 }
 
-/// Extract the inode to the given path. Single threaded.
+/// Extract the inode to the given path.
-pub fn extractTo(self: Inode, archive: *Archive, path: []const u8, options: ExtractionOptions) !void {
+pub fn extractTo(self: Inode, alloc: std.mem.Allocator, archive: Archive, path: []const u8, options: ExtractionOptions) !void {
+    if (options.threads > 1) return self.extractToThreaded(alloc, archive, path, options); // We go to a dedicated function for mutli-threaded
     switch (self.hdr.inode_type) {
         .dir, .ext_dir => {
             // Removing any trailing separators since that's the easiest path forward.
-            if (path[path.len - 1] == '/') return self.extractTo(archive, path[0 .. path.len - 1], options);
+            if (path[path.len - 1] == '/') return self.extractTo(alloc, archive, path[0 .. path.len - 1], options);
             std.fs.cwd().makeDir(path) catch |err| {
                 if (err != std.fs.Dir.MakeError.PathAlreadyExists) return err;
             };
-            var alloc = archive.allocator();
+            const entries = try self.dirEntries(alloc, archive);
-            const entries = try self.dirEntries(alloc, archive.*);
             defer {
                 for (entries) |entry| entry.deinit(alloc);
                 alloc.free(entries);
@@ -178,12 +188,12 @@ pub fn extractTo(self: Inode, archive: *Archive, path: []const u8, options: Extr
 
                 var inode: Inode = try readFromEntry(alloc, archive, entry);
                 defer inode.deinit(alloc);
-                try inode.extractTo(archive, new_path, options);
+                try inode.extractTo(alloc, archive, new_path, options);
             }
         },
-        .file, .ext_file => try self.extractRegFile(archive.allocator(), archive, path, options),
+        .file, .ext_file => try self.extractRegFile(alloc, archive, path, options),
         .symlink, .ext_symlink => try self.extractSymlink(path),
-        else => try self.extractDevice(archive, path, options),
+        else => try self.extractDevice(alloc, archive, path, options),
     }
 }
 
@@ -202,23 +212,24 @@ const Parent = struct {
     wg: WaitGroup,
     mut: Mutex = .{},
 
-    fn create(alloc: std.mem.Allocator, hdr: Header, archive: *Archive, path: []const u8, options: ExtractionOptions, dir_size: usize) !*Parent {
+    fn create(alloc: std.mem.Allocator, hdr: Header, archive: Archive, path: []const u8, options: ExtractionOptions, dir_size: usize) !*Parent {
         const out = try alloc.create(Parent);
         errdefer alloc.destroy(out);
         out.* = .{
             .alloc = alloc,
 
             .path = path,
-            .uid = try archive.id(hdr.uid_idx),
+            .uid = try archive.id_table.get(alloc, hdr.uid_idx),
-            .gid = try archive.id(hdr.gid_idx),
+            .gid = try archive.id_table.get(alloc, hdr.gid_idx),
             .perm = hdr.permissions,
             .mod_time = hdr.mod_time,
 
             .ignore_permissions = options.ignore_permissions,
             .ignore_xattr = options.ignore_xattr,
 
-            .wg = .{ .state = .init(dir_size) },
+            .wg = .{},
         };
+        out.wg.startMany(dir_size);
         return out;
     }
 
@@ -232,7 +243,7 @@ const Parent = struct {
         defer p.alloc.destroy(p);
         var fil = try std.fs.cwd().openFile(p.path, .{});
         defer fil.close();
-        const time = p.mod_time * 1000000000;
+        const time = @as(i128, p.mod_time) * 1000000000;
         try fil.updateTimes(time, time);
         if (p.ignore_permissions) {
             try fil.chmod(p.perm);
@@ -243,36 +254,26 @@ const Parent = struct {
 
 /// Extract the inode to the given path. Multi-threaded.
 /// Functions identically to extractTo on all but regular files and directories.
-///
+fn extractToThreaded(self: Inode, alloc: std.mem.Allocator, archive: Archive, path: []const u8, options: ExtractionOptions) !void {
-/// If threads <= 1, then this just calls extractTo.
-pub fn extractToThreaded(self: Inode, archive: *Archive, path: []const u8, options: ExtractionOptions, threads: usize) !void {
-    if (threads <= 1) return self.extractTo(archive, path, options);
     switch (self.hdr.inode_type) {
         .dir, .ext_dir => {
             // Removing any trailing separators since that's the easiest path forward.
-            if (path[path.len - 1] == '/') return self.extractToThreaded(archive, path[0 .. path.len - 1], options, threads);
+            if (path[path.len - 1] == '/') return self.extractToThreaded(alloc, archive, path[0 .. path.len - 1], options);
-
-            // Fixed Allocator
-            // const mem_buf = archive.allocator().alloc(u8, 2 * 1024 * 1024 * 1024);
-            // defer archive.allocator().free(mem_buf);
-            // var fixed_alloc: std.heap.FixedBufferAllocator = .init(mem_buf);
-            // const alloc = fixed_alloc.threadSafeAllocator();
 
             // Arena Allocator
-            var arena_alloc: std.heap.ArenaAllocator = .init(archive.allocator());
+            var arena_alloc: std.heap.ArenaAllocator = .init(alloc);
             defer arena_alloc.deinit();
             var thread_alloc: std.heap.ThreadSafeAllocator = .{ .child_allocator = arena_alloc.allocator() };
-            const alloc = thread_alloc.allocator();
 
             var wg: WaitGroup = .{};
             // defer if(!options.ignore_permissions) perms.?.deinit(alloc); We don't need to do this due to ArenaAllocator
             var pool: Pool = undefined;
-            try pool.init(.{ .allocator = alloc, .n_jobs = threads - 1 });
+            try pool.init(.{ .allocator = alloc, .n_jobs = options.threads - 1 });
             defer pool.deinit();
             var out_err: ?anyerror = null;
 
             wg.start();
-            self.extractThread(alloc, archive, path, options, &wg, &pool, &out_err, null);
+            self.extractThread(thread_alloc.allocator(), archive, path, options, &wg, &pool, &out_err, null);
             pool.waitAndWork(&wg);
             if (out_err != null) return out_err.?;
 
@@ -282,17 +283,17 @@ pub fn extractToThreaded(self: Inode, archive: *Archive, path: []const u8, optio
             try fil.updateTimes(time, time);
             if (options.ignore_permissions) {
                 try fil.chmod(self.hdr.permissions);
-                try fil.chown(try archive.id(self.hdr.uid_idx), try archive.id(self.hdr.gid_idx));
+                try fil.chown(try archive.id_table.get(alloc, self.hdr.uid_idx), try archive.id_table.get(alloc, self.hdr.gid_idx));
             }
         },
         .file, .ext_file => {
-            const alloc = archive.allocator();
-
             var pool: Pool = undefined;
-            try pool.init(.{ .allocator = alloc, .n_jobs = threads });
+            try pool.init(.{ .allocator = alloc, .n_jobs = options.threads - 1 });
             defer pool.deinit();
 
-            try self.extractRegFileThreaded(alloc, archive, path, options, &pool);
+            var thread_alloc: std.heap.ThreadSafeAllocator = .{ .child_allocator = alloc };
+
+            try self.extractRegFileThreaded(thread_alloc.allocator(), archive, path, options, &pool);
 
             var fil = try std.fs.cwd().openFile(path, .{});
             defer fil.close();
@@ -300,18 +301,18 @@ pub fn extractToThreaded(self: Inode, archive: *Archive, path: []const u8, optio
             try fil.updateTimes(time, time);
             if (!options.ignore_permissions) {
                 try fil.chmod(self.hdr.permissions);
-                try fil.chown(try archive.id(self.hdr.uid_idx), try archive.id(self.hdr.gid_idx));
+                try fil.chown(try archive.id_table.get(alloc, self.hdr.uid_idx), try archive.id_table.get(alloc, self.hdr.gid_idx));
             }
         },
         .symlink, .ext_symlink => try self.extractSymlink(path),
-        else => try self.extractDevice(archive, path, options),
+        else => try self.extractDevice(alloc, archive, path, options),
     }
 }
 
 fn extractThreadEntry(
     entry: DirEntry,
     alloc: std.mem.Allocator,
-    archive: *Archive,
+    archive: Archive,
     path: []const u8,
     options: ExtractionOptions,
     wg: *WaitGroup,
@@ -339,7 +340,7 @@ fn extractThreadEntry(
 fn extractThread(
     self: Inode,
     alloc: std.mem.Allocator,
-    archive: *Archive,
+    archive: Archive,
     path: []const u8,
     options: ExtractionOptions,
     wg: *WaitGroup,
@@ -352,7 +353,7 @@ fn extractThread(
     defer {
         if (parent != null) parent.?.finish() catch |err| {
             if (options.verbose)
-                options.verbose_writer.?.print("Error setting folder permission to {s}: {}\n", .{ path, err }) catch {};
+                options.verbose_writer.?.print("Error setting folder permission to {s}: {}\n", .{ parent.?.path, err }) catch {};
             out_err.* = err;
         };
         wg.finish();
@@ -367,7 +368,7 @@ fn extractThread(
                 return;
             };
 
-            const entries = self.dirEntries(alloc, archive.*) catch |err| {
+            const entries = self.dirEntries(alloc, archive) catch |err| {
                 if (options.verbose)
                     options.verbose_writer.?.print("Error getting directory entries for inode #{} (extracting to {s}): {}\n", .{ self.hdr.num, path, err }) catch {};
                 out_err.* = err;
@@ -399,6 +400,10 @@ fn extractThread(
                     },
                 ) catch |err| {
                     wg.finish();
+                    p.finish() catch |e| {
+                        if (options.verbose)
+                            options.verbose_writer.?.print("Error setting folder permission to {s}: {}\n", .{ p.path, e }) catch {};
+                    };
                     if (options.verbose)
                         options.verbose_writer.?.print("Error starting extraction thread: {}\n", .{err}) catch {};
                     out_err.* = err;
@@ -421,7 +426,7 @@ fn extractThread(
             };
         },
         else => {
-            self.extractDevice(archive, path, options) catch |err| {
+            self.extractDevice(alloc, archive, path, options) catch |err| {
                 if (options.verbose)
                     options.verbose_writer.?.print("Error extracting device/IPC inode #{} to {s}: {}\n", .{ self.hdr.num, path, err }) catch {};
                 out_err.* = err;
@@ -433,7 +438,7 @@ fn extractThread(
 /// Optionally set owner & permissions.
 ///
 /// Assumes the inode is a file or ext_file type.
-fn extractRegFile(self: Inode, alloc: std.mem.Allocator, archive: *Archive, path: []const u8, options: ExtractionOptions) !void {
+fn extractRegFile(self: Inode, alloc: std.mem.Allocator, archive: Archive, path: []const u8, options: ExtractionOptions) !void {
     var fil = try std.fs.cwd().createFile(path, .{ .exclusive = true });
     defer fil.close();
     var wrt = fil.writer(&[0]u8{});
@@ -446,14 +451,14 @@ fn extractRegFile(self: Inode, alloc: std.mem.Allocator, archive: *Archive, path
     try fil.updateTimes(time, time);
     if (!options.ignore_permissions) {
         try fil.chmod(self.hdr.permissions);
-        try fil.chown(try archive.id(self.hdr.uid_idx), try archive.id(self.hdr.gid_idx));
+        try fil.chown(try archive.id_table.get(alloc, self.hdr.uid_idx), try archive.id_table.get(alloc, self.hdr.gid_idx));
     }
 }
 /// Extract the inode file contents to the given path threadedly.
 /// pool is used to spawn threads.
 ///
 /// Assumes the inode is a file or ext_file type.
-fn extractRegFileThreaded(self: Inode, alloc: std.mem.Allocator, archive: *Archive, path: []const u8, options: ExtractionOptions, pool: *Pool) !void {
+fn extractRegFileThreaded(self: Inode, alloc: std.mem.Allocator, archive: Archive, path: []const u8, options: ExtractionOptions, pool: *Pool) !void {
     var fil = try std.fs.cwd().createFile(path, .{});
     defer fil.close();
     var data = try self.threadedDataReader(alloc, archive);
@@ -463,7 +468,7 @@ fn extractRegFileThreaded(self: Inode, alloc: std.mem.Allocator, archive: *Archi
     try fil.updateTimes(time, time);
     if (!options.ignore_permissions) {
         try fil.chmod(self.hdr.permissions);
-        try fil.chown(try archive.id(self.hdr.uid_idx), try archive.id(self.hdr.gid_idx));
+        try fil.chown(try archive.id_table.get(alloc, self.hdr.uid_idx), try archive.id_table.get(alloc, self.hdr.gid_idx));
     }
 }
 /// Creates the symlink described by the inode.
@@ -481,7 +486,7 @@ fn extractSymlink(self: Inode, path: []const u8) !void {
 ///
 /// Optionally set owner & permissions.
 /// Assumes the inode is a char_dev, block_dev, fifo, socket, or their extended counterparts.
-fn extractDevice(self: Inode, archive: *Archive, path: []const u8, options: ExtractionOptions) !void {
+fn extractDevice(self: Inode, alloc: std.mem.Allocator, archive: Archive, path: []const u8, options: ExtractionOptions) !void {
     var mode: u32 = undefined;
     var dev: u32 = 0;
     switch (self.data) {
@@ -530,7 +535,7 @@ fn extractDevice(self: Inode, archive: *Archive, path: []const u8, options: Extr
     try fil.updateTimes(time, time);
     if (!options.ignore_permissions) {
         try fil.chmod(self.hdr.permissions);
-        try fil.chown(try archive.id(self.hdr.uid_idx), try archive.id(self.hdr.gid_idx));
+        try fil.chown(try archive.id_table.get(alloc, self.hdr.uid_idx), try archive.id_table.get(alloc, self.hdr.gid_idx));
     }
     if (!options.ignore_xattr) {
         // TODO

src/options.zig

@@ -5,6 +5,8 @@ const Writer = std.Io.Writer;
 
 const ExtractionOptions = @This();
 
+/// The amount of threads to use for extraction.
+threads: usize,
 /// Don't set the file's owner & permissions after extraction
 ignore_permissions: bool = false,
 /// Don't set xattr values. Currently xattrs are never set anyway.
@@ -16,9 +18,16 @@ verbose: bool = false,
 /// Where to print verbose log.
 verbose_writer: ?*Writer = null,
 
-pub const Default: ExtractionOptions = .{};
+pub const SingleThreaded: ExtractionOptions = .{ .threads = 1 };
-pub fn VerboseDefault(wrt: *Writer) ExtractionOptions {
+/// Use std.Thread.getCpuCount threads for extraction.
+pub fn Default() !ExtractionOptions {
     return .{
+        .threads = try std.Thread.getCpuCount(),
+    };
+}
+pub fn VerboseDefault(wrt: *Writer) !ExtractionOptions {
+    return .{
+        .threads = try std.Thread.getCpuCount(),
         .verbose = true,
         .verbose_writer = wrt,
     };

src/table.zig

@@ -16,61 +16,34 @@ pub fn Table(T: anytype) type {
 
         const VALS_PER_BLOCK = 8192 / @sizeOf(T);
 
-        alloc: std.mem.Allocator,
         fil: OffsetFile,
         decomp: DecompFn,
-        tab_start: u64,
 
-        tab: std.AutoHashMap(u32, []T),
+        tab_start: u64,
         values: u32,
 
-        mut: Mutex = .{},
+        pub fn init(fil: OffsetFile, decomp: DecompFn, tab_start: u64, values: u32) Self {
-
-        pub fn init(alloc: std.mem.Allocator, fil: OffsetFile, decomp: DecompFn, tab_start: u64, values: u32) !Self {
             return .{
-                .alloc = alloc,
                 .fil = fil,
                 .decomp = decomp,
-                .tab_start = tab_start,
 
-                .tab = .init(alloc),
+                .tab_start = tab_start,
                 .values = values,
             };
         }
 
-        pub fn deinit(self: *Self) void {
+        pub fn get(self: Self, alloc: std.mem.Allocator, idx: u32) !T {
-            var iter = self.tab.valueIterator();
-            while (iter.next()) |s| {
-                self.alloc.free(s.*);
-            }
-            self.tab.deinit();
-        }
-
-        pub fn get(self: *Self, idx: u32) !T {
-            if (idx >= self.values) return TableError.InvalidIndex;
             const block_num = idx / VALS_PER_BLOCK;
             const idx_offset = idx - (block_num * VALS_PER_BLOCK);
-            if (self.tab.contains(block_num)) {
-                const block = self.tab.get(block_num).?;
-                return block[idx_offset];
-            }
-            self.mut.lock();
-            defer self.mut.unlock();
-            // Double check in case of race condition..
-            if (self.tab.contains(block_num)) {
-                const block = self.tab.get(block_num).?;
-                return block[idx_offset];
-            }
             const is_last = (self.values - 1) / VALS_PER_BLOCK == block_num;
             const slice_size = if (is_last) self.values - (block_num * VALS_PER_BLOCK) else VALS_PER_BLOCK;
-            const slice = try self.alloc.alloc(T, slice_size);
+            var slice: [VALS_PER_BLOCK]T = undefined;
             var rdr = try self.fil.readerAt(self.tab_start + (8 * block_num), &[0]u8{});
             var offset: u64 = 0;
             try rdr.interface.readSliceEndian(u64, @ptrCast(&offset), .little);
             rdr = try self.fil.readerAt(offset, &[0]u8{});
-            var meta: MetadataReader = .init(self.alloc, &rdr.interface, self.decomp);
+            var meta: MetadataReader = .init(alloc, &rdr.interface, self.decomp);
-            try meta.interface.readSliceEndian(T, @ptrCast(slice), .little);
+            try meta.interface.readSliceEndian(T, slice[0..slice_size], .little);
-            try self.tab.put(block_num, slice);
             return slice[idx_offset];
         }
     };

src/test.zig

@@ -9,8 +9,7 @@ const TestArchive = "testing/LinuxPATest.sfs";
 test "Basics" {
     var fil = try std.fs.cwd().openFile(TestArchive, .{});
     defer fil.close();
-    var sfs: Archive = try .init(std.testing.allocator, fil);
+    const sfs: Archive = try .init(fil, 0);
-    defer sfs.deinit();
     if (sfs.super != LinuxPATestCorrectSuperblock) {
         std.debug.print("Superblock wrong\nShould be: {}\n\nis: {}\n", .{ LinuxPATestCorrectSuperblock, sfs.super });
         return error.BadSuperblock;
@@ -24,11 +23,10 @@ test "ExtractSingleFile" {
     std.fs.cwd().deleteFile(TestFileExtractLocation) catch {};
     var fil = try std.fs.cwd().openFile(TestArchive, .{});
     defer fil.close();
-    var sfs: Archive = try .init(std.testing.allocator, fil);
+    var sfs: Archive = try .init(fil, 0);
-    defer sfs.deinit();
+    var test_fil = try sfs.open(std.testing.allocator, TestFile);
-    var test_fil = try sfs.open(TestFile);
     defer test_fil.deinit();
-    try test_fil.extract(TestFileExtractLocation, .Default);
+    try test_fil.extract(std.testing.allocator, TestFileExtractLocation, try .Default());
     //TODO: validate extracted file.
 }
 
@@ -38,9 +36,8 @@ test "ExtractCompleteArchive" {
     std.fs.cwd().deleteTree(TestFullExtractLocation) catch {};
     var fil = try std.fs.cwd().openFile(TestArchive, .{});
     defer fil.close();
-    var sfs: Archive = try .init(std.testing.allocator, fil);
+    var sfs: Archive = try .init(fil, 0);
-    defer sfs.deinit();
+    try sfs.extract(std.testing.allocator, TestFullExtractLocation, try .Default());
-    try sfs.extract(TestFullExtractLocation, .Default);
 }
 
 const LinuxPATestCorrectSuperblock: Superblock = .{

src/util/data.zig

@@ -29,13 +29,16 @@ interface: Reader,
 cur_offset: u64,
 block_idx: u32 = 0,
 
-pub fn init(alloc: std.mem.Allocator, archive: Archive, blocks: []BlockSize, start: u64, size: u64) DataReader {
+pub fn init(alloc: std.mem.Allocator, archive: Archive, blocks: []BlockSize, start: u64, size: u64, frag_offset: u32, frag_entry: ?FragEntry) DataReader {
     return .{
         .alloc = alloc,
         .fil = archive.fil,
         .decomp = archive.decomp,
         .block_size = archive.super.block_size,
         .blocks = blocks,
+
+        .frag = frag_entry,
+        .frag_offset = frag_offset,
         .size = size,
         .cur_offset = start,
         .interface = .{
@@ -56,11 +59,6 @@ pub fn deinit(self: *DataReader) void {
     self.interface.seek = 0;
 }
 
-pub fn addFragment(self: *DataReader, entry: FragEntry, frag_offset: u32) void {
-    self.frag = entry;
-    self.frag_offset = frag_offset;
-}
-
 fn numBlocks(self: DataReader) usize {
     var res = self.blocks.len;
     if (self.frag != null) res += 1;

src/util/data_threaded.zig

@@ -28,7 +28,7 @@ size: u64,
 
 start_offset: u64,
 
-pub fn init(alloc: std.mem.Allocator, archive: Archive, blocks: []BlockSize, start: u64, size: u64) ThreadedDataReader {
+pub fn init(alloc: std.mem.Allocator, archive: Archive, blocks: []BlockSize, start: u64, size: u64, frag_offset: u32, frag_entry: ?FragEntry) ThreadedDataReader {
     return .{
         .alloc = alloc,
         .fil = archive.fil,
@@ -37,12 +37,10 @@ pub fn init(alloc: std.mem.Allocator, archive: Archive, blocks: []BlockSize, sta
         .blocks = blocks,
         .size = size,
         .start_offset = start,
-    };
-}
 
-pub fn addFragment(self: *ThreadedDataReader, entry: FragEntry, frag_offset: u32) void {
+        .frag_offset = frag_offset,
-    self.frag = entry;
+        .frag = frag_entry,
-    self.frag_offset = frag_offset;
+    };
 }
 
 fn numBlocks(self: ThreadedDataReader) usize {